Preparation of aqueous dispersions of synthetic rubbers



Patented Oct. 5, 1 948 PREPARATION OF AQUEOUS DISPERSIONS OF SYNTHETIC RUBBERS Charles F. Brown, Bethany, W. Va., assignor to United States Rubber Company, New York, I N. Y., a corporation of New Jersey No Drawing. Application January 29, 1947,

Serial No. 725,172

This invention relates to method of preparing aqueous dispersions of certain synthetic resins, more particularlyaqueous dispersions of certain synthetic resins on soaps as the dispersing agents.

Natural rubber, as is known, may readily be dispersed in water by milling or otherwise plasticizing the rubber, incorporating a hydrophilic colloidal dispersing agent, for example soap, solubilized casein, or colloidal clay,- and adding water while stretching and kneading the plasticized mass, as in an internal mixer, such as a Werner 8: Pfleiderer type mixer, until an inversion of phase takes place, and the rubber becomes dispersed in the aqueous medium. Gums, bitumens, and cellulose esters have been similarly dispersed in water. Many synthetic resins, even after the addition of conventional plasticizing agents, cannot be dispersed in water with soap as the dispersing agent because such synthetic resins are resistant to and will not absorb soapforming acids or soaps in such a manner that the addition of water thereto, as in an internal mixer, will cause an inversion of phase and, dispersion of the synthetic resin in the aqueous medium. In these cases, the synthetic resin containing the soap breaks up in small pieces on addition of the water and the soap merely exudes to the surface of the pieces of synthetic resin.

By the present invention, aqueous dispersions of certain synthetic resins may readily be prepared with soaps as the dispersing agents.

In carrying out my invention, the heat-reaction product of rosin, an alkanolamine, an alkylene glycol, and a dimerized acid of a vegetable drying oil is mixed with the synthetic resin before dispersing the resin on the soap. This reaction product acts to improve the receptiveness of the synthetic resin to soap, whereby after the soap is milled in, water may be added as in an internal mixer until inversion of phase readily takes place and the synthetic resin becomes dispersed, together with the added heat-reaction product, in the aqueous medium containing the soap. The heat-reaction product of rosin, an

alkanolamine, an alkylene glycol, and a dimerized acid of a vegetable drying oil, and the method of preparing the same, is disclosed in my copending application Serial No. 507,295, filed October 22, 1943, now Patent No. 2,416,433, granted February 16 Claims. (Cl. 260-235) nal reactants.

25.1947. As disclosed in that case, the glycol and dimerized acid of a vegetable drying oil may first be reacted to form a so-called polyester which itseli is a known commercial synthetic resin, sold under the trade names Norepol and Agripol. The polyester, or the glycol and dimerized acid of a vegetable drying oil, is reacted at elevated temperatures with rosin and an alkanolamine to form the heat-reaction product which is usedin the present invention to aid in dispersing certain difficultly dispersible synthetic resins in water. Examples of the preparation of the heat-reaction product, according to my prior patent application Serial No. 507,295, are given below.

The heat-reaction product may beproduced by-heating for about 5 to 15 hours at a temperature from about 180 C. to 300 C., a mix containing rosin, an alkanolamine, an alkylene glycol and a dimerized acid of a vegetable drying oil, or an equivalent mix containing rosin, an alkanolamine and a polyester. The alkanolamine may be a monoor dior tri-substituted alkanoiamine, or a mixture thereof, e. g. monoethanolamine, diethanolamine, tri-ethanolamine, although the tri-substituted alkanolamines are preferred. The term "polyester refers to the synthetic resin obtained by reacting a glycol with a dimerized acid of a vegetable drying oil, such as soy bean oil, tung oil, linseed oil, or other unsaturated vegetable oil acid. By dimerized is meant the combination of two molecules of the unsaturated acid by addition polymerization. These are the conventional meanings of the terms.

The reactions taking place between the com-' ponents present are varied and complex. The polyester when added as such probably breaks down into its several reacting groups, which groups or bodies react with other bodies present to give various products differing from the origi- The dimerized acid and glycol, when added separately, either provide such reactive groups, or may react to give a polyester, which'in turn may give up reactive bodies as postulated. The dimerized acid and glycol, when added separately, should be added to a weight equivalent to the weight of the polyester. For example, 87.5 parts of dimerized acids of'soy bean oil, and 12.5 parts of ethylene glycol, are equivalent to parts of the corresponding polyester. In some cases, an excess of the glycol may be used beyond that entering into combination. As such, the glycol seems to act as a plasticizer and does not materially change the basic heat- .reaction product or resin formed. The proportion of the reactants may be varied over a wide range and they may be admixed with other materials before, during, or after the reaction; for example, a polyvinyl acetal resin may be additionally added. Proportions, by

weight, are exemplified by the following:

' Parts Rosin 25-100 Triethanolamine' 25-100 Polyester 50-200 85 to about 100 parts of the polyester based on each 100 parts 01 the rosin.

The following Examples I to IV, in which the parts are by weight, are

The "polyester and that or Example 11 is a combination prepared from a dimerized acid derived from such as soy bean 011, said dimerized acid being reacted with ethylene glycol and the reaction product containing about 12%% ethylene glycol. It is sold under the trade name Norepol." The rosin and the amine are mixed and heated to about 180 C. until the ingredients form a homogeneous solution. Then the polyester is added and'the reaction mixture is heated together in a suitable container at 200-230 C. for about 9 or hours; or until insipid gelling takes place. At the indication of gelling, the mixture is dumped from the reaction vessel and allowed to cool. The product is a dark, very sticky, adhesive, gel-like -resin that'is insoluble in all of the common solvents, except the benzenold and chlorinated hydrocarbons.

Example II Parts Rosin 100 Triethanolamine 100 Polyester 85 Polyvinyl butyral resin 15 I Example IV A heat-reaction product corresponding to that produced in Example II is obtained from:

Parts Rosin 100 Triethanolamine 100 Dimerized acids 74.4 Ethylene glycol 10.6 Polyvinyl butyral resin 15 The reactants are heated together as in Example 11, and the products obtained are substantially identical in characteristics with those from Example 11.

Products such as the above and illustrated in previous Examples I to IV, will be termed heatreaction products or rosin, an alkanolamine, a glycol and a dimerized acid of a vegetable drying oil, or a dimerized unsaturated acid of a vegetable 011. Such resinous heat-reaction products may readily be milled into synthetic resins, With certain synthetic resins. the heat-reaction product will permit the admixture oi soaps with the synthetic resin mass and give an inversion of phase on addition of water with dispersing 01' the synthetic resin and added heat-reaction product in the aqueous medium. The amount of the heatreaction product added to the synthetic resin is not critical, additions of from 5 to parts of the heat-reaction product of the above examples per 100 parts of synthetic resin eilectively aiding the dispersing oi the synthetic resin in water. In general. increased amounts of the heat-reaction product give increased viscosities, and increased tack to films laid down from the dispersions.

Synthetic resins which have been dispersed in water on soap as the dispersing agent with the aid of the above heat-reaction products are polyisobutylene, and copolymers of isobutylene with up to 15% by weight of the copolymer oi. a conjugated diene. Polyisobutylene is commercially vknown as Vistanex. Illustrative of copolymers of -thetic resins according to the present invention which may utilize the heat-reaction products of The reaction mixture is heated as in Example I.

The product has characteristics substantially identical with that cited in Example 1 except that the composition is stiller and stronger.

Example III It is not always necessary that the polyester be added as such. The ingredients may be added separately. The following example is illustrative:

Parts Rosin 100 Triethanolamine 100 Dimerized a 87.25 Ethylene gla 12.75

prior Examples I to IV as dispersing aids for the synthetic resins prior to dispersing on soap. The soap may be added as such or formed in-situ in the synthetic resin mass. The soap may be a conventional soap dispersing agent, such as an alkali-metal, ammonium, alkylamine, alkanolamine. or morpholine scab. All parts in the following examples are by weight.

Example V One part 0! stearic acid and 1 part of water were added on the mill. The mill batch was then placed in a Werner 8: Pfleiderer mixer and 5 parts more of stearic acid added. After-thorough incorporation of the stearic acid, a small amount of water was added with 1.5 parts of potassium hydroxide dissolved in a small amount of water to neutralize the stearic acid and form the potas-- 15 to inversion 0! phase.

Example VI v 100 parts of commercial Butyl Rubber (copolymer of isobutylene with about 1 to 2% isoprene) were mixed on a mill with 20 parts of the heat-reaction product of Example III. The

plasticized mass was transferred to a Werner 8: Pileiderer mixer where 6 parts of stearic acid were added with continuous mixing together with a small amount of water followed by 1.3 parts of sodium hydroxide dissolved in a small amount of water to form the sodium soap. Water was then added with'continuous kneading and stretching of the mass in the mixer in the usual manner until inversion of phase took place and a stable aqueous dispersion was obtained.

' invention using soap as the dispersing agent, soap dispersions being the most diflicult dispersions of synthetic resins to prepare due to the resistance 'of the synthetic resins to the softening effects of soap-forming acids and soaps. However, the heat-reaction products such as shown in Examples I to IV, will effectively aid in the dispersing of the synthetic resins on other dispersing agents than soaps, such as proteins, for example solubilized casein, or colloidal clay.

In view of the many changes and modifications thLt may be made without departing from the principles underlying the invention, reference should be made to the appended claims for an understanding of the scope of the protection aflorded the invention.

This application is a continuation-in-part of my application Serial No. 559,651 filed October 20, 1944, now Patent No. 2,419,816, granted April 29, 1947.

Having thus described my invention, what I- claim and desire to protect by Letters Patent is:

1. The method of preparing an aqueous dispersion of synthetic resin selected from the group consisting of polyisobutylene, and copolymers of isobutylene with up to 15% by weight of the copolymer of a conjugated diene selected from the group consisting of butadiene-1,3 and isoprene, which comprises mixing with such synthetic resin a heat-reaction product, at a temperature in the range of between about 180 C. and 300 C., of

a mix containing rosin, an alkanolamine, an alkylene glycol and a dimerized acid of a vegetable drying oil, and also mixing with the synthetic resin a hydrophilic colloidal dispersing agent selected from the group consisting of soaps, proteins, solubilized casein and colloidal clay, and adding water until an inversion of phase takes place.

2. The method of preparing an aqueous dispersion of synthetic resin selected from the group consisting oi polyisobutylene, and copolymers of isobutylene with up to 15% by weight of the copolymer of a. conjugated diene selected from the group consisting of butadiene-l,3 and isoprene, which comprises mixing with such synthetic resin a heat-reaction product, at a temperature in the range of between about 180 C. and 300 C., of a mix containing rosin, an alkanolamine, ethylene glycol and a dimerized acid of a vegetable drying I 6 oil, and also mixing with the'synthetic resin a soap, and adding water until an inversion of phase takes place.

3. The method of preparing an aqueous dispersion oi synthetic resin selected from the group consisting of polyisobutylene, and copolymers of isobutylene with up to by weight of the copolymer of a conjugated diene selected from the group consisting of butadiene-1,3 and isoprene, which comprises mixing with such synthetic resin a heat-reaction product, at a temperature in the range of between about 180 C. and 300 C., of a mix containing rosin, an alkanolamine, ethylene glycol and dimerized acid of soy bean oil, and also mixing with the synthetic resin a hydrophilic colloidal dispersing agent selected from the group consisting oi soaps, proteins, solubilized casein and colloidal clay, and adding water until an inversion of phase takes place.

4. The method of preparing an aqueous dispersion of synthetic resin selected from the group consisting of polyisobutylene, and copolymers of isobutylene with up to 15% by weight of said copolymer of a conjugated diene selected from the group consisting of butadiene-Lii and isoprene, which comprises mixing with such synthetic resin a. heat-reaction product, at a temperature in the -range of between about 180 C. and 300 C., of

a mix containing rosin, an alkanolamine, an alkylene glycol and dimerized acid of soy bean oil, and also mixing with the synthetic resin a soap, and adding water until an inversion of phase takes place.

5. The method of preparing an aqueous disproduct, at a temperature in the range of between about 180 C. and 300? C., of a-mix containing rosin, an alkanolamine, an alkylene glycol and dimerized acid of soy bean oil, and also mixing with the polyisobutylene a soap, and adding water until an inversion of phase takes place.

7. The method of preparing an aqueous dispersion of a copolymer of isobutylene and 1 to 10% by weight of the copolymer of isoprene which comprises mixing with said copolymer a heat-reaction product, at a temperature in the range of between about C. and 300 C., of a mix containing rosin, an alkanolamine, ethylene glycol and a dimerized acid of a vegetable drying oil, and also mixing with the copolymer hydrophilic colloidal dispersing agent selected from the group consisting of soaps, proteins, solubilized casein and colloidal clay, and adding water until an inversion of phase takes place.

8. The method of preparing an aqueous dispersion of a copolymer, of isobutylene and 1 to 10% by weight of the copolymer of isoprene which comprises mixing with said copolymer a heat-reaction product, at a temperature in the range of betweenabout 180 C. and 300 C., of a mix containing rosin, an alkanolamine, an alkylene glycol and dimerized acid of soy bean oil, and also mixing with the copolymer a soap. and adding water until an inversion of phase takes place.

spasm 0.. A- composition or matter containing dispersed particles or a mixture of synthetic resin selected from the group consisting oi polyisobutylene, and copolymers of isobutylene with up to 15% by weight of the copolymer of a conjugated diene selected irom the group consisting of hutadiene-1,3 and isoprene, with a heat-reaction product, at a temperature in the range of between about 180 C. and 300 0., of a mix containing rosin, an alkanolamine, an'alhlene glycol and a dimeriaed acid of a vegetable drying oil, in an aqueous medium containing a hydrophilic colloidal dispersing agent selected from the group consisting of soaps. proteins, solubilized casein and colloidal clay.

10. A "oi .matterecontaining dispersed particles oi a mixture of synthetic resin selected from the group consisting of polyisobutylene, and copolymers of isobutylene with up to 15% by weight of the copolymer a coniugated diene selected from the group consisting of hutadiene-1,3 and isoprene, with a heat-reaction product, at a temperature in the range or between about 180 C. and 300 C., of a mix containing rosin, an alkanolamine, ethylene glycol and a dimerized acid of a vegetable drying oil, in an ..aqueous medium containing soap.

11. A composition of matter containing dispersed particles of a mixture of synthetic resin selected from the group consisting of polyisobutylene, and copolymers of isobutylene with up to by weight oithe copolymers of a conjugated diene selected from the group consisting of hutadiene-1,3 and isoprene, with a heat-reaction product, at a temperature in the range oi between about 180 C. and 300 0., of a mix containing rosin. an alkanolamine, ethylene glycol and dimerised acid or soy bean oil, in an aqueous medium containing a hydrophilic colloidal dispersing agent selected from the group consisting of soaps, proteins, solubllized casein and colloidal clay.

12. A composition of matter containing dispersed particles of a mixture of synthetic resin selected from the group consisting of polyisobutylene, and copolymers of isobutylene with up to 15% by. weight of the copolymer of a con- .lugated diene selected from the groupconsisting with a heat-reaction product, at a temperature in the range of between about 180 C. and 800 C., of a mix containing rosin, an glkanolamine, an

, alkylene glycol and dimerized acid of soy bean oil,

in an aqueous medium containing a hydrophilic colloidal dispersing agent selected from the group consisting of soaps, proteins, solubilized casein and colloidal clay.

14. A composition of matter containing dispersed particles or a mixture or polyisobutylene with a heat-reaction product, at a temperature in the range oi! between about C. and 300 C., of a mix containing rosin, an alkanolamine, ethylene glycol and a dimerized acid of a vegetable drying oil, in an aqueous medium containing soap.

15. A composition of matter containing dispersed particles of a mixture of a copolymer of isobutylene and 1 to 10% by weight oi the copolymer of isoprene, with a heat-reaction product, at a temperature in the range of between about 180 C. and 300 6., of a mix containing rosin. an alkanolamine, an allrylene glycol and dimerized acid of soy bean oil, in an aqueous medium containing a hydrophilic colloidal dispersing agent selected from the group consisting of soaps, proteins, solubilized casein and colloidal clay.

16. A composition of matter containing dispersed particles or a mixture oi a copolymer of isobutylene and 1 to 10% by weight of the copolymer of isoprene, with a heat-reaction product, at a temperature in the range of between about 180 C. and 300 6., of a mix containing rosin, an alkanolamine, ethylene glycol and a dimerized acid of a vegetable drying oil, in an aqueous medium containing soap.

CHARLES F. BROWN.

No references cited. 

